Abstract
The daily outgoing longwave radiation (OLR) field in boreal summer shows significant power spectrum peaks on quasi-biweekly (10–20-day) and intraseasonal (20-80-day) timescales over the Indo-western Pacific warm pool, especially over the South China Sea and Bay of Bengal. The quasi-biweekly oscillation (QBWO) originates from off-equatorial western North Pacific, and is characterized by a northwest-southeast oriented wave train pattern, propagating northwestward. The intraseasonal oscillation (ISO), on the other hand, originates from the equatorial Indian Ocean and propagates eastward and northward.
Why the equatorial mode possesses a 20–80-day periodicity while the off-equatorial mode favors a 10–20-day periodicity is investigated through idealized numerical experiments with a 2.5-layer atmospheric model. In the off-equatorial region, the model simulates, under a realistic three-dimensional summer mean flow, the most unstable mode that has a wave train pattern with a typical zonal wavelength of 6000 km and a period of 10–20 days, propagating northwestward. This is in contrast to the equatorial region, where a Madden-Julian oscillation (MJO) like mode with a planetary (wavenumber-1) zonal scale and a period ranging from 20 to 80 days is simulated. Sensitivity experiments with different initial conditions indicate that the QBWO is an intrinsic mode of the atmosphere in boreal summer in the off-equatorial Indo-western Pacific region under the summer mean state, while the MJO is the most unstable mode in the equatorial region.
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References
Chatterjee, P., and B. N. Goswami, 2004: Structure, genesis and scale selection of the tropical quasi-biweekly mode. Quart. J. Roy. Meteor. Soc., 130, 1171–1194, doi: https://doi.org/10.1256/qj.03.133.
Chen, T.-C, M.-C. Yen, and S.-P. Weng, 2000: Interaction between the summer monsoons in East Asia and the South China Sea: Intraseasonal monsoon modes. J. Atmos. Sci., 57, 1373–1392, doi: https://doi.org/10.1175/1520-0469(2000)057<1373:IBTSMI>2.0.CO;2.
Christiano, L. J., and T. J. Fitzgerald, 2003: The band pass filter. Int. Econ. Rev., 44, 435–465, doi: https://doi.org/10.1111/1468-2354.t01-1-00076.
Drbohlav, H.-K. L., and B. Wang, 2005: Mechanism of the northward-propagating intraseasonal oscillation: Insights from a zonally symmetric model. J. Climate., 18, 952–972, doi: https://doi.org/10.1175/JCLI3306.1.
Goswami, P., and V. Mathew, 1994: A mechanism of scale selection in tropical circulation at observed intraseasonal frequencies. J. Atmos. Sci., 51, 3155–3166, doi: https://doi.org/10.1175/15200469(1994)051<3155:AMOSSI>2.0.CO;2.
Hendon, H. H., and M. L. Salby, 1994: The life cycle of the Mad-den-Julian oscillation. J. Atmos. Sci., 51, 2225–2237, doi:10.1175/1520-0469(1994)051<2225:TLCOTM>2.0.CO;2.
Hsu, H.-H., and C.-H. Weng, 2001: Northwestward propagation of the intraseasonal oscillation in the western North Pacific during the boreal summer: Structure and mechanism. J. Climate., 14, 3834–3850, doi: https://doi.org/10.1175/1520-0442(2001)014<3834:NPOTIO>2.0.CO;2.
Hsu, P.-C., and T. Li, 2012: Role of the boundary layer moisture asymmetry in causing the eastward propagation of the Madden-Julian oscillation. J. Climate., 25, 4914–4931, doi: https://doi.org/10.1175/JCLI-D-11-00310.1.
Jiang, X.-A., and T. Li, 2005: Reinitiation of the boreal summer intraseasonal oscillation in the tropical Indian Ocean. J. Climate., 18, 3777–3795, doi: https://doi.org/10.1175/JCLI3516.1.
Jiang, X. N., T. Li, and B. Wang, 2004: Structures and mechanisms of the northward propagating boreal summer intraseasonal oscillation. J. Climate., 17, 1022–1039, doi: https://doi.org/10.1175/1520-0442(2004)017<1022:SAMOTN>2.0.CO;2.
Kanamitsu, M., W. Ebisuzaki, J. Woollen, et al., 2002: NCEP-DOE AMIP-II Reanalysis (R-2). Bull. Amer. Meteor. Soc., 83, 1631–1644, doi: https://doi.org/10.1175/BAMS-83-11-1631.
Lau, K.-M., G. J. Yang, and S. H. Shen, 1988: Seasonal and intraseasonal climatology of summer monsoon rainfall over East Asia. Mon. Wea. Rev., 116, 18–37, doi: https://doi.org/10.1175/1520-0493(1988)116<0018:SAICOS>2.0.CO;2.
Li, C. H., T. Li, A. L. Lin, et al., 2015: Relationship between summer rainfall anomalies and sub-seasonal oscillations in South China. Climate Dyn., 44, 423–439, doi: https://doi.org/10.1007/s00382-014-2172-y.
Li, T., 2006: Origin of the summertime synoptic-scale wave train in the western North Pacific. J. Atmos. Sci., 63, 1093–1102, doi: https://doi.org/10.1175/JAS3676.1.
Li, T., 2014: Recent advance in understanding the dynamics of the Madden-Julian oscillation. J. Meteor. Res., 28, 1–33, doi: https://doi.org/10.1007/s13351-014-3087-6.
Li, T., and B. Wang, 2005: A review on the western North Pacific monsoon: Synoptic-to-interannual variabilities. Terr. Atmos. Oceanic Sci,16, 285–314, doi: https://doi.org/10.3319/TAO2005.162.285(A).
Li, T., and C. H. Zhou, 2009: Planetary scale selection of the Madden-Julian oscillation. J. Atmos. Sci., 66, 2429–2443, doi: https://doi.org/10.1175/2009JAS2968.1.
Li, T., and P.-C. Hsu, 2018: Fundamentals of Tropical Climate Dynamics. Springer, Cham, 229 pp, doi: https://doi.org/10.1007/978-3-319-59597-9.
Li, T., P. Liu, X. Fu, et al., 2006: Spatiotemporal structures and mechanisms of the tropospheric biennial oscillation in the Indo-Pacific warm ocean regions. J. Climate., 19, 3070–3087, doi: https://doi.org/10.1175/JCLI3736.1.
Li, T., L. Wang, M. Peng, et al, 2018: A paper on the tropical intraseasonal oscillation published in 1963 in a Chinese journal. Bull. Amer. Meteor. Soc., 99, 1765–1779, doi: https://doi.org/10.1175/BAMS-D-17-0216.1.
Li, T. M., and B. Wang, 1994: The influence of sea surface temperature on the tropical intraseasonal oscillation: A numerical study. Mon. Wea. Rev., 122, 2349–2362, doi: https://doi.org/10.1175/1520-0493(1994)122<2349:TIOSST>2.0.CO;2.
Madden, R. A., and P. R. Julian, 1971: Detection of a 40–50 day oscillation in the zonal wind in the tropical Pacific. J. Atmos. Sci., 28, 702–708, doi: https://doi.org/10.1175/1520-0469(1971)<0280702:DOADOI>2.0.CO;2.
Madden, R. A., and P. R. Julian, 1972: Description of global-scale circulation cells in the tropics with a 40–50 day period. J. Atmos. Sci., 29, 1109–1123, doi: https://doi.org/10.1175/1520-0469(1972)029<1109:DOGSCC>2.0.CO;2.
Matsuno, T., 1966: Quasi-geostrophic motions in the equatorial area. J. Meteor. Soc. Japan., 44, 25–43, doi: https://doi.org/10.2151/jmsj1965.44.1_25.
Murakami, T., 1980: Empirical orthogonal function analysis of satellite-observed outgoing longwave radiation during summer. Mon. Wea. Rev., 108, 205–222, doi: https://doi.org/10.1175/1520-0493(1980)108<0205:EOFAOS>2.0.CO;2.
Teng, H. Y., and B. Wang, 2003: Interannual variations of the boreal summer intraseasonal oscillation in the Asian-Pacific region. J. Climate,6, 3572–3584, doi: https://doi.org/10.1175/1520-0442(2003)016<3572:IVOTBS>2.0.CO;2.
Wang, B., 1988: Dynamics of tropical low-frequency waves: An analysis of the moist Kelvin wave. J. Atmos. Sci,45, 2051–2065, doi: https://doi.org/10.1175/1520-0469(1988)045<2051DOTLFW>2.0.CO;2.
Wang, B., and H. Rui, 1990: Synoptic climatology of transient tropical intraseasonal convection anomalies: 1975–1985. Meteor. Atmos. Phys., 44, 43–61, doi: https://doi.org/10.1007/BF01026810.
Wang, B., and T. M. Li, 1994: Convective interaction with boundary-layer dynamics in the development of a tropical intraseasonal system. J. Atmos. Sci., 51, 1386–1400, doi: https://doi.org/10.1175/1520-0469(1994)051<1386:CIWBLD>2.0.CO;2.
Wang, B., and X. S. Xie, 1997: A model for the boreal summer intraseasonal oscillation. J. Atmos. Sci., 54, 72–86, doi: https://doi.org/10.1175/1520-0469(1997)054<0072:AMFTBS>2.0.CO;2.
Wen, M., T. Li, R. H. Zhang, et al, 2010: Structure and origin of the quasi-biweekly oscillation over the tropical Indian Ocean in boreal spring. J. Atmos. Sci., 67, 1965–1982, doi: https://doi.org/10.1175/2009JAS3105.1.
Xie, Y.-B., S.-J. Chen, Y.-L. Zhang, et al., 1963: A preliminarily statistic and synoptic study about the basic currents over southeastern Asia and the initiation of typhoons. Acta Meteor. Sinica., 3, 206–217, doi: https://doi.org/10.11676/qxxb1963.020. (in Chinese)
Xie, Y.-B., S.-J. Chen, Y.-L. Zhang, et al., 2018: A preliminarily statistic and synoptic study about the basic currents over southeastern Asia and the initiation of typhoons (English Edition). J. Meteor. Res., 32, 661–669, doi: https://doi.org/10.1007/s13351-018-8888-6.
Xu, Z. Q., T. Li, and K. Fan, 2017: The weakened intensity of the atmospheric quasi-biweekly oscillation over the western North Pacific during late summer around the late 1990s. J. Climate., 30, 9807–9826, doi: https://doi.org/10.1175/JCLI-D-16-0759.1.
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Supported by the National Key Research and Development Program of China (2018YFC1505805), US NOAA (NA18OAR4310298), US NSF (AGS-1643297), National Natural Science Foundation of China (41875069, 41575052, and 41575043), and Fund for Collaborative Innovation of Meteorological Science in East China (QYHZ201608). This is SOEST contribution number 10892, IPRC contribution number 1424, and ESMC number 298.
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Zhang, Y., Li, T., Gao, J. et al. Origins of Quasi-Biweekly and Intraseasonal Oscillations over the South China Sea and Bay of Bengal and Scale Selection of Unstable Equatorial and Off-Equatorial Modes. J Meteorol Res 34, 137–149 (2020). https://doi.org/10.1007/s13351-020-9109-7
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DOI: https://doi.org/10.1007/s13351-020-9109-7